Telephone system.



UNITED STATES PATENT OFFICE. OSCAR M. LEIGH, or GENOA, ILLINOIS,assrcnon '10 CRAGRAFT, LEIGH ELECTRIC COMPANY, or GEN-0A, ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

To all whom it may coricem Be it known, that -I, OSCAR LEIoH, a

citizen of the United States, residing at Genoa, in the county of Dekalband State of Illinois, have invented a certain new and usefulImprovement in Telephone Systems,

of which the following'is' a full, clear, con-v cise, and exactdescription, reference being had to the accompanying drawings, forming apart of this specification.

My invention relates to telephone systems and is designed moreparticularly for use in connection with intercommunication betweentelephones connected to a local battery exchange and telephonesassociated with a common battery exchange. The: system is.

such that the local battery exchange apparatus may be much simpler.

In the preferred form of the invention I utilize a local batterytelephone which may be connected by means of a common battery trunkcircuit with a common battery ex}. change, and which local battery:telephone has facilities for. furnishing the proper clear-.

ing out signals .to the common battery exchange. i in the local batterytelephone has means for automatically calling the local battery ex-:

change when the receiver is removed from the hook.

I will explain one embodiment .of my invention more in detail byreference to the accompanying drawing in which: I

Figure 1 illustrates a system constructed inaccordance with myinvention, and Fig. 2 is a diagrammatic View of a cord circuit whichmaybe employed at the local battery exchange for the local service.

It will of course be understood that I am describing specifically oneembodiment of my invention herein, but this specific description is notintended to limit the broad features of my invention, the specificdevices and apparatus shown herein being merely illustrative of myinvention.

In the drawing I show a part of the exchange apparatus of a commonbattery exchange A, and apparatus at a localbattery exchange B which isnecessary for anunderstanding of my invention.

At G I illustrate a substation instrument circuit which I prefer toemploy in connection with this system. This particular substationcircuit is more specifically set forth and claimed in my copendingapplication'Se- In the preferred form shown here'- Patented May 28,1912.

rial No; 561,651, filed May 16, 1910. At the A substation C I'have aswitchhook 1 carrying the receiver 2, the transmitter 3, the secondary 5of an induction coil, the primary A of an induction coil, thetransmitter battery 6 and an auxiliary signal sendingbattery 7 I alsoshow a polarized ringer 8 which through the agency of a condenser 9 isbridged across the line wires 10 and 11 which connect the substationinstrument with the private branchexchange B. The line wires 10 and 11terminate in a jack 12 with which is associated a line drop 13 so"arranged to be disconnected by the spring 1:4 whenever a plug isinserted in the jack.

The transmitter circuit is connectedto one pole'of the battery 6 and thespring L5. The

- other'terminal of the battery 6 is connected ;to the switchhookproper 1. One terminal of the receiver circuit is connected to thespring 16 andgthe line wire 11 .is connected to the spring 17 and thesprings 18 and 19.

A spring 20 is a part of and moves with the switchhook 1 and is underthe control of a weight 21. The receiver circuit thus extends from linewire 10, receiver 2, secondary 5, spring-16, spring 17, and line wire 11whenever the receiver is removed from the hook. In such cases thetransmitter circuit extends from the battery 6,rtransmitter 3,

primary 4:, spring 15,

hook lever 1 to the other terminal of the battery 6. lVhen the receiver1 is uponthe hook the circuit be- 7 tween line wires 10 and 11 is openso faras direct currents'are concerned at the substation. Alternatingcurrents. for operating the signal 8 through the condenserr can bereceived, however, asis well understood. Whenever the receiver isremoved from the hook or replaced thereon a momentary contact isestablished between the spring 20 and either of the springs 18 and19,which contact is of suflicient duration tooperate the line drop 3 or theclearing out drop of the local battery cord circuit which will beexplained later. This momentary cont-act is,

however, broken dueto the influence of the weight 21 when theswitchhook" lever 1 has finally comet-o rest in either its uppermost orlowermost limiting position, so that normally while talking or normallywhen the receiver is on the hook, no circuit is complete through'thesprings 18 or 19' and 20. The local battery cord circuit set forth in 2comprises the plugs 22 and 23 which are adapted to unite varioussubstations and are adapted to receive clearing out signals by means ofthe clearing out drops 24 and 25. Condensers 26 may be employed so as toget double clearing out service.

In accordance with my invention, I may make the clearing out drops ofthe local battery cord circuit very low wound, say for instance, fiftyohms, and I find that for local service such a low winding is notprohibitive. In this event, I may dispense with the auxiliary signalsending battery 7 and obtain signals merely through the agency of thetalking battery 6 as will be readily apparent, and this aids me in con-.

structing a very inexpensive branch exchange switchboard for thisservice. In the magneto cord circuit of Fig. 2, I have omitted theringing and listening keys and also their connections extending to thesignaling device and the operators talking circuit, the connection ofwhich devices is well understood and need not be given at length herein.At the common battery exchange A I have also shown a cord circuit havingthe plugs 27, 28, which cord circuit is used in connection with jacks 29of which there may be a great number for the various lines entering theexchange, but of which but one is illustrated. These jacks at the commonbattery exchange may, of course, be multiplied as desired. In thiscommon battery cord circuit I show the terminals 29 29 for the ringinggenerator and 30, 30 for the operators talking circuit. Condensers 31are likewise shown and clearing out relays 32, 32. At this commonbattery exchange I have a common battery 33 which furnishes the currentfor all entering lines, all of which entering lines may be provided witha line relay 34, line lamp 35 and impedance coils 36, 36.

Whenever a receiver is removed from the hook the relay 34 is energizedto light thev line lamp and when the cord circuit is connected the linelamp is extinguished, as is well understood, and the correspondingclearing out relay 32 is under the control of the substation switchhookor other circuit closing device.

To provide for talking service between the common battery exchange A andthe local battery exchange B, I employ a trunk circuit having the linewires 37, 38 for uniting the two exchanges and this trunk circuit 37, 38ends at the common battery exchange in the usual apparatus as explained.The trunk circuit ends at the local battery ex change in a plug 39adapted for use in connection with the jack 12. The plug 39 controls theplug switch 40 having springs 41, 42, 43 and 44 so arranged that whenthe plug is withdrawn springs 41 and 42 are connected and springs 43 and44 are connected, whereas when the plug 39 is in its normal seat switch40, contact between springs 41 and 42 is opened and likewise the contactbetween springs 43 and 44.

A ringing and listening key is provided having the listening springs 45and 46 which through the interposition of springs 47 and a condenser 48connect with the operators set. The spring 46 cotiperates with springs49 and 50 whose purpose will be presently explained. A relay 51 isserially associated with the plug ended cord circuit and a condenser 52is bridged around its terminals. Ringing springs 53, 53 are provided,the ringing circuit, however, not being shown for the sake of clearness.At the end of the trunk circuit in the local battery exchange a drop 54is provided which is bridged across the said trunk through theinterposition of a condenser 55. The relay 51 has an armature 56 whichcontrols a back contact 57 connected with a clearing out lamp 58, whichclearing out lamp is also associated with the spring 41 of the plug seatswitch 40. A battery 59 for clearing out purposes is included in thislamp circuit. The relay 51 also has a second armature 60 having a backcontact 61 which controls a circuit through the holding relay 62, whichholding relay has its circuit likewise controlled by the springs 43, 44.This holding relay 62 has an armature 63 having a front contact 64.

Assume now that the subscriber at station G wishes to communicate withthe common battery exchange, the said subscriber at this station removesthe receiver which through the agency of the springs 19 and 20 sends anautomatic signal to operate the drop 13. The operator at station B usespreferably at first hand the local battery cord circuit and upon findingthat the call is not a local one but a long distance one, removes thelocal cord circuit and inserts the plug 39 of the plug ended trunkleading to the exchange A. As the circuit for direct current is closedat station 0 through the receiver and the secondary winding 5, thisinsertion of the plug 39 on the part of the operator at station Boperates the relay 34 and signals the operator at the station A. Theoperator at this station inserts the plug 28 and then completes theconnection. When the plug 39 is inserted relay 51 is energized toattract its armatures and thus opens the circuit through the lamp 58.Now when the conversation is completed the receiver 2 is restored, andthis opens the direct current circuit at the substation, therebybreaking the circuit through relay 32 and the opera tor at station Adisconnected. Circuit through the relay 51 is thereby also broken andits armature 56 contacts with the con tact 57, thereby energizing thelamp 58 and notifying the operator at station B to disconnect. Nowshould the call be in the re- This is due to verse manner, the operatorat station A upon having a call for the local battery exchange B, or oneof its subscribers, merely inserts the plug 28 into the jack 29 andsends the necessary ringing current over the trunk circuit 37 38, whichthereupon energizes the drop 54 to display a signal to the localoperator at B. The local operator at B operates the listening keysprings and 46, thereby placing herself into communication with theoperator at A and noting the connection desired. 'She thereuponcompletes the connection by inserting the plug 39 into the jack 12 ofthe desired line and calls the subscriber corresponding thereto byoperating the ringing springs 53, 53. The removal of the plug 39 fromthe plug seat switch 40 closes the circuit through the lamp 58 and asthe said relay 51 is still deenergized the operator at station B isprovided with a clearing out signal. The clearing out relay 32 of thecentral station A, however, is operated to extinguish its associatedclearing out lamp, immediately the operator at the station B operatesher listening springs 45 and 46. v the springs 49 and 50 being connectedtogether when the spring 46 is operated as this closes a circuit fromthe conductor 38, spring 50, spring-49, relay 62 to conductor37. Therelay 62 thereupon attracts its armature- 63 and closes a circuitextending from conductor 38, contact61,

armature 60, springs 43 and 44, contact 64, armature 63, relay 62, toconductor 37. The clearing out relay 32 thus remains in such a conditionas to keep the clearing out lamp deenergized by virtue of the saidholding relay 62. During this time the lamp 58, however, remainslighted.- Now when the called subscriber at station C responds theremoval of the receiver from the hook causes the energization of relay51 which thereupon attracts its armature 56 to extinguish clearing outlamp 58 and also attracts its armature 60 to break the circuit throughthe holding relay 62. When the conversation is completed the subscriberat station C hangs up and this again operates the relay 32 so that theoperator at station A breaks the connection. The consequentdeenergization ofrelay 51 permits its armature 56 to retract, tothereupon operate the clearing out lamp 58 in response to which theoperator at station B manually disconnects the cord circuit from theline circuit. 1

It will thus be seen that a highly efiicient service condition isestablished between a local battery substation and a common batteryexchange through the interposition of a local battery exchange. Thelocal battery substation clears out similar to a common batterytelephone and thus provides additional advantageous operatingconditions.

The general character of the invention will thus be understood as willlikewise the fact that many modifications may be made without departingfrom its spirit.

Having, however, thus described one embodiment of my invention, what Iclaim as new and desire to secure by Letters Patent is: p

1. A telephone system comprising a com mon battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,a trunk circuit between said exchanges, and a local battery telephoneassociated with said local battery exchange and having provision forcontroll1ng the'said signal receiving devices aforesaid.

2. A telephone system comprising a com mon battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,a trunk circuit between said exchanges, and a local battery telephoneassociated with said local battery exchange and having provision forcontrolling'the said signal receiving devices aforesaid over acontinuous conducting circuit including said trunk circuit and extendingfrom said, telephone to said common battery exchange.

3. A telephone system comprising a common battery exchange, line .andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, atrunk circuitbetween said exchanges, and a local" battery telephone associated withsaid local batter-y exchange and having provision for controlling thesaid signal receiving devices aforesaid. V

4. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, and a local battery telephone associated withsaid local battery exchange and having provision for controlling thesaid signal receiving devices afore said over a continuous conductingcircuit including said trunk circuit and extending from said telephoneto said common battery exchange.

5. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,a trunk circuit between said exchanges, and a local battery telephoneassociated with said local battery exchange and having provision forautomatically controlling the said signal receiving devices exchanges,and a local battery telephone associated with said local batteryexchange and having provision for automatically controlling the saidsignal receiving devices aforesaid over a continuous conducting circuitincluding said trunk circuit and extending from said telephone to saidcommon battery exchange.

7. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, and a local battery telephone associated withsaid local battery exchange and having provision for automaticallycontrolling the said signal receiv ing devices aforesaid.

8. A telephone system comprising a com mon battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, and a local battery telephone associated withsaid local battery exchange and having provision for automaticallycontrolling the said signal receiving devices aforesaid over acontinuous conducting circuit including said trunk circuit and extendingfrom said telephone to said common battery exchange.

9. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, a local battery tele phone associated with saidlocal battery exchange, having provision for automatically controllingthe common battery exchange signal receiving devices, and a source ofcurrent supply to automatically control the local battery exchangesignal receiving devices.

10. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, a local battery telephone associated with saidlocal battery exchange, having provision for automatically controllingthe common battery exchange signal receiving devices, and a source ofcurrent supply to automatically control the local battery exchangesignal receiving devices, through the agency of its switchhook lever.

11. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,a trunk circuit between said exchanges, and a local battery telephoneassociated with said local battery exchange and having provision forcontrolling the said signal receiving devices aforesaid, said localbattery telephone having a local signal receiving circuit whoseobstruction to direct current is sufiicient so as to prevent operationof signal receiving devices aforesaid.

12. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local bat teryexchange, a trunk circuit between said exchanges, and a local batterytelephone associated with said local battery exchange and havingprovision for controlling the said signal receiving devices aforesaidover a continuous conducting circuit including said trunk circuit andextending from said telephone to said common battery exchange, saidlocal battery telephone having a local signal receiving circuit whoseobstruction to direct current is sufficient so as to prevent operationof signal receiving devices aforesaid.

13. A telephone system comprising a com mon battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, and a local battery telephone associated withsaid local battery exchange and having provision for controlling thesaid signal receiving devices aforesaid, said local battery telephonehaving a local signal receiving circuit whose obstruction to directcurrent is suflicient so as to prevent operation of signal receivingdevices aforesaid.

' 14. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, and a local battery telephone associated withsaid local battery exchange and having provision for controlling thesaid signal receiving devices aforesaid over a continuous conductingcircuit including said trunk circuit and extending from said telephoneto said common battery exchange, said local battery telephone having alocal signal receiving circuit whose obstruction to direct current issufficient so as to prevent operation of signal receiving devicesaforesai 15. A telephone system comprising a common battery exchange,line and clearing out signal receiving devices thereat, a local batteryexchange, a trunk circuit between said exchanges, and a local batterytelephone associated with said local battery exchange and havingprovision for automatically controlling the said signal receivingdevices aforesaid, said local battery telephone having a local signalreceiving circuit whose obstruction to direct current is sufficient soas to prevent operation of signal receiving devices aforesaid.

16. A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,a trunk circuit between said exchanges, and a local battery telephoneassociated with said local battery exchange and having provision forautomatically controlling the said signal creceiving devices aforesaidover a continuous conducting circuit including said trunk circuit andextending fromsaid telephone to said common batteryoexchange, said localbattery telephone having a local signal receiving circuit whoseobstruction to direct current is suflicientso as to prevent operation ofsignal receiving devices aforesaid.

17 A telephone system comprising a common battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, and a local battery telephone associated withsaid local battery exchange and having provision for automaticallycontrolling the said signal receiving devices aforesaid, said localbattery tele-v phone having a local signal'receiving cir- I cuit whoseobstruction to direct current is suflicient so as to prevent operationof signal receiving devices aforesaid;

18. A telephone system comprising acornmon battery exchange, line andclearing out signal receiving devices thereat, a local battery exchange,line and clearing out signal receiving devices thereat, a trunk circuitbetween said exchanges, and a local battery telephone associated withsaid local battery exchange and having provision for automaticallycontrolling the said signal receiv:

ing devices aforesaid, over a continuous conducting circuit includingsaid trunk circuit and extending from said telephone to said commonbattery exchange, said local battery telephone having a local signalreceiving circuit whose obstruction to direct current is suflicient soas to prevent operation of signal receiving devices aforesaid.

In witness whereof, I hereunto subscribe my name this 18th day of MarchA. D., 1911.

OSCAR M. LEIGH.

Witnesses:

HAZEL JONES, O. M. WERMICH.

Copies of this patent may be obtained for five cents each, by addrWashington, D. C.

essing the Commissioner of Patents,

